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This study investigates the microbially induced calcium carbonate precipitation (MICP) in repair mortar, focusing on the impact of calcium precursor dosage and bacterial strain selection. C6H10CaO6·xH2O and (CH3COO)2Ca·xH2O were used as calcium precursors at dosages of 0.1, 0.25, and 0.4 M with Bacillus subtilis VEB4, Priestia megaterium TSB16, and Halobacillus halophilus MCC2188microbes. Quantitative assessment of precipitate and optimization of precursor dosages were conducted before making mortar cube specimens of size 70.6 × 70.6 × 70.6 mm with bacterial spores and nutrients immobilized in Modified Expanded Perlite. Cracked cube specimens underwent automated wet-dry cycles of 12 h daily for 60 days to induce healing. Comparative analysis of biomortar specimens showed P. megateriumas the most effective in compressive strength recovery (up to 89.33%) and crack healing with a maximum healed crack width of 0.64 mm, followed by B. subtiliswith significant CSR improvements. H. halophilus, less efficient in non-saline conditions, healed cracks up to 0.48 mm. Calcium lactate was considered the better calcium source choice for B. subtilisand P. megateriumstrains, whereas calcium acetate improved MICP by H. halophilus. Microstructural analysis of healed precipitates collected from cracked cubes identified distinct morphology of MICP and the presence of polymorphs viz, calcite, aragonite, and vaterite. Tailored selection and dosage of calcium precursors for each strain significantly enhanced MICP and improved the quality of healing products in cracks, advancing the understanding of self-healing construction biomaterials.

Virgin coconut oil (VCO) is renowned for its numerous health benefits and widespread culinary applications. Fermentation is one of the simplest cold press methods used for the production of VCO. However, the longer fermentation time affects the scale ability and VCO quality. To enhance its production process and improve overall product quality, this study investigates the impact of using aerobic fermented skimmed coconut milk starter (SCMS) at different concentrations of the culture (5–15%) to maximize the yield and quality and minimize the cost, time, and energy during the production of virgin coconut oil (VCO) in fermentation process. It was observed that 24-h-old SCMS at 10% concentration recorded a maximum yield (19.2%) in the 19-h fermentation process. Individual and interactive effects of culture type (24-h and 48-h fermented SCMS) and its concentration significantly affect yield; however, its effects on physical (moisture content, viscosity, specific gravity, and refractive index) and chemical profile (free fatty acid, peroxide value, acid value, saponification value, iodine value, and total phenolic content) of the resultant VCO remain insignificant. The physicochemical properties of VCO prepared to utilize the SCMS-induced fermentation method confirmed the standards stipulated by the Food Safety and Standards Authority of India (FSSAI) and Asian and Pacific Coconut Community (APCC). SCMS is the cheapest alternative that could be exploited to enhance the fermentation rate during the production of VCO.

A total of 20 bacteria including seven fluorescent Pseudomonasspp. and 13 Bacillusspp., out of 483 previously isolated bacteria from rhizosphere and roots of healthy and high yielding coconut palms from major coconut growing States in India, were tested for their growth promotion efficacy on West Coast Tall variety coconut seedlings. Firstly, they were characterized for (i) ability to grow under different environmental stress parameters, (ii) carbon use pattern determined with BIOLOG and (iii) their genetic diversity using RFLP analysis. Seedling response to PGPR inoculation was measured by recording the leaf numbers, girth, root and shoot fresh and dry biomass weights in relation to nutrient uptake efficiency and plant–microbe feedback. Tolerance studies for abiotic parameters showed that Pseudomonasspp. were efficient in growing in 5.2 to 8.2 pH, 15–30 °C temperatures and 0.5 to 10% NaCl concentration, whereas, Bacillusspp. grew well in pH 4.2–8.2, temperatures 20–40 °C and 0.5 to 10% NaCl concentration. The BIOLOG analysis highlighted Bacillusspp. to be more suited to coconut rhizosphere milieu compared to Pseudomonasspp. based on the carbon oxidizing capabilities. Among the four different enzymes used in RFLP analysis, HaeIII and HinfI were observed to be most discriminatory for Bacillusand PseudomonasPGPR genera, respectively. Inoculation of coconut seedlings resulted in significant increase in seedling length (1–16% increase), girth of the seedlings (7–27%) and dry weight (7–38% increase) compared with control. Between the two genera, the gram-positive Bacillusspp. were seen to outperform the gram-negative Pseudomonasspp. in the growth promotion studies. The endophytic B. megateriumTEB2 (T2) resulted in highest dry weight biomass increase (38%) in coconut seedlings followed by another endophytic B. cereusHEB10 (T3) and a rhizospheric isolate B. licheniformisRSB14 (T17) indicating their potential for development of bioinoculant formulation. Our studies, thus, offer a bouquet of indigenous PGPR, possessing abiotic stress tolerant traits, to choose upon to develop either an effective singular bioinoculant or a minimum effective microbiome set (MEMS) for raising vigorous and robust coconut seedlings for supply to coconut farmers.

Mycorrhizal fungi are widespread in agricultural systems and are especially relevant for organic agriculture. A study was conducted to assess diversity in the arbuscular mycorrhizal (AM) fungi associated with coconut and arecanut intercropping systems of Kasaragod and Thiruvananthapuram districts of Kerala. Mycorrhizal parameters like spore density, root colonization, species richness, and relative occurrence of species were recorded. Coconut cropping system was found to be densely vegetated with diverse AM fungi, Glomusspp., Gigasporaspp., and Acaulosporaspp. The diversity of fungal species was found to be maximum in the high density multiple species cropping system plot of CPCRI, Kasaragod with coconut as the main crop and banana, pepper as intercrops and least in farmers’ plot of Mogral Puthur, Kasaragod with arecanut as main crop and banana as the intercrop. A total of fourteen AM fungi were identified from coconut and arecanut intercropping systems. Glomusaggregatum, Funneliformis mosseae, and Rhizophagus fasiculatumwere observed in both the cropping systems studied. Among the six edaphic factors analysed, an inverse relationship of mycorrhizal population with soil pH and soil phosphorous was observed. An abundance of P-solubilizers, fluorescent Pseudomonasspp., N-fixers, Bacillusspp., and Trichodermaspp. were observed in the rhizosphere, with Bacillusspp. showing the maximum association with AM fungi. The higher AMF colonization in coconut cropping system imply that the AM fungi colonization is primarily dependent on the host plant rather than the climatic/edaphic components of an area.Mycorrhizal fungi are widespread in agricultural systems and are especially relevant for organic agriculture. A study was conducted to assess diversity in the arbuscular mycorrhizal (AM) fungi associated with coconut and arecanut intercropping systems of Kasaragod and Thiruvananthapuram districts of Kerala. Mycorrhizal parameters like spore density, root colonization, species richness, and relative occurrence of species were recorded. Coconut cropping system was found to be densely vegetated with diverse AM fungi, Glomusspp., Gigasporaspp., and Acaulosporaspp. The diversity of fungal species was found to be maximum in the high density multiple species cropping system plot of CPCRI, Kasaragod with coconut as the main crop and banana, pepper as intercrops and least in farmers’ plot of Mogral Puthur, Kasaragod with arecanut as main crop and banana as the intercrop. A total of fourteen AM fungi were identified from coconut and arecanut intercropping systems. Glomusaggregatum, Funneliformis mosseae, and Rhizophagus fasiculatumwere observed in both the cropping systems studied. Among the six edaphic factors analysed, an inverse relationship of mycorrhizal population with soil pH and soil phosphorous was observed. An abundance of P-solubilizers, fluorescent Pseudomonasspp., N-fixers, Bacillusspp., and Trichodermaspp. were observed in the rhizosphere, with Bacillusspp. showing the maximum association with AM fungi. The higher AMF colonization in coconut cropping system imply that the AM fungi colonization is primarily dependent on the host plant rather than the climatic/edaphic components of an area.

The rhinoceros beetle, Oryctes rhinocerosL., is an economically important pest of the coconut palm. Management of this pest has been accomplished using microbial agents viz., Oryctesvirus (OrV) and an entomofungal pathogen Metarhizium anisopliae. Recently an opportunistic bacterial pathogen Pseudomonas alcaligeneshas also been noticed to cause septicaemia in the grubs when under stress. To unravel the influence of abiotic weather factors and the interactions amongst these microbial pathogens, a 3 year study was conducted from September 1996 to August 1999 in three of the southern districts of Kerala, India. Of the 6627 grubs and 307 adults collected from various breeding sites of the pest, 5% of the grubs and 22% of the adults had natural virus infection, 3% larvae died of M. anisopliaemycosis and 20% larvae succumbed to bacterial septicaemia. Oryctesvirus infection in grubs and adults was negatively correlated to minimum temperature (correlation co-efficient, r= −0.4, and −0.6 respectively, sample size, n = 0). Increase in relative humidity increased the fungal activity (r= 0.8) whereas, maximum temperature had a negative impact (r= −0.7). Occurrence of virus infection in grubs and adults was positively correlated (r= 0.6), supporting the contention of active transmission of the virus pathogen between these two stages. The bacterial septicaemia in the grubs was marginally correlated with virus infection and P. alcaligenesundermined the efficiency of the virus pathogen.

Aspergillus flavusisolated from naturally infected leaf-eating caterpillar (Opisina arenosellaW.), lace bug (Stephanitis typicaD.) and plant hopper (Proutista moestaWestwood), insect pests of the coconut palm, were tested for aflatoxin (AT) production by employing various media formulations. These A. flavusisolates were earlier found to be entomopathogenic in laboratory bioassays. A laboratory contaminant and four standard aflatoxigenic A. flavusisolates were also included in this study as reference strains. All A. flavusisolates were tested on seven AT detection media: coconut extract agar, coconut extract-sodium desoxycholate agar, coconut extract-ascorbic acid agar, coconut extract-Czapek Dox agar, coconut extract-milk powder agar, 10% commercial coconut milk powder agar (CCMPA) and 20% CCMPA. Only two isolates of A. flavus, originally isolated from O. arenosellaand P. moesta, produced ATs. AT production was detected within 48 h of incubation and was detected continually up to 1 month. These AT-producing A. flavusisolates also produced bright yellow pigmentation in the medium. Of all the seven media used for AT detection, CCMPA (10%) was found to be the best one, followed by 20% CCMPA, for direct and rapid AT detection. AT production was not necessary for pathogenicity in the insects.

The coconut palm is an important plantation crop in India, where it is cultivated on 1.796 million hectares. The rhinoceros beetle, Oryctes rhinocerosL. (Coleoptera: Scarabaeidae) is a serious pest of coconut throughout India and southeast Asia, causing an estimated 10% yield loss in the crop. Successful biological control of this pest could be achieved using the non-occluded Oryctesvirus (syn. Baculovirus oryctesor Oryctes baculovirus). This review provides an account of this microbial agent, its biology, effects and impact, production and maintenance and alternative hosts, particularly in the context of the Indian situation. It also proposes future areas for investigation on the virus, in order to achieve its commercial viability and more widespread use. Le palmier cocotier est une importante culture de plantation en Inde, où il est cultivé sur 1,796 millions d’hectares. Le scarabée rhinocéros, Oryctes rhinocerosL. (Coleoptera: Scarabaeidae) est un sérieux ravageur du cocotier en Inde et en Asie du Sud Est, responsable de pertes de récolte estimées à 10%. Un contrôle biologique efficace de ce ravageur pourrait être obtenu en utilisant le virion non inclus du virus d’Oryctes(syn. Baculovirus oryctesou baculovirus de l’Oryctes). Cette revue bibliographique fait le point sur cet agent microbien, sa biologie, son efficacité et son impact, sa production et sa maintenance ainsi que sur ses hôtes alternatifs, en particulier dans le contexte de l’Inde. Elle propose également de futurs domaines de recherches sur ce virus, afin d’aboutir à sa viabilité commerciale et à une plus grande utilisation.

Four plant growth promoting rhizobacterial (PGPR) isolates belonging to genera Bacillusand Enterobacterand two Bradyrhizobiumspp. (Vigna) strains Cog 15 and S 24 were selected for competition studies. PGPR isolates did not antagonize Bradyrhizobiumstrains Cog 15 and S 24 on plates. In unsterile soil, co-inoculations of PGPR and Bradyrhizohiumstrains failed to show any conclusive influence on nodulation and ARA at 50 days of plant growth. PGPR isolates had a direct effect on shoot biomass development, N content and grain yield when tested with Bradyrhizohiumstrain S 24, after 50 and 80 days of plant growth.